feat: ✨ pass on existing search params to redirected url

src/index.ts

@@ -14,16 +14,20 @@ app.get('/', (c) =>
 );
 
 app.get('*', async (c) => {
+  const incomingUrl = new URL(c.req.url);
+  const existingSearchParams = incomingUrl.searchParams;
+
   // Get the URL pathname as input text minus the leading "/"
-  const text = new URL(c.req.url).pathname.slice(1);
+  const text = incomingUrl.pathname.slice(1);
   const { NOT_FOUND_REDIRECT_URL, REFERRER_TEXT } = c.env;
   const url = await c.env.GO_URLS.get(text);
 
   if (!url) {
     if (NOT_FOUND_REDIRECT_URL) {
       const redirectUrl = appendReferrerTextToUrl(
         NOT_FOUND_REDIRECT_URL,
-        REFERRER_TEXT
+        REFERRER_TEXT,
+        existingSearchParams
       );
       return c.redirect(redirectUrl);
     }
@@ -32,7 +36,7 @@ app.get('*', async (c) => {
     return c.text('Not found', 404);
   }
 
-  const urlWithRef = appendReferrerTextToUrl(url, REFERRER_TEXT);
+  const urlWithRef = appendReferrerTextToUrl(url, REFERRER_TEXT, existingSearchParams);
 
   return c.redirect(urlWithRef, 307);
 })

src/util.ts

@@ -1,7 +1,23 @@
-export const appendReferrerTextToUrl = (url = '/', referrerText: string) => {
+export const appendReferrerTextToUrl = (
+  url = '/',
+  referrerText: string,
+  existingSearchParams: URLSearchParams
+) => {
   if (!referrerText) return url;
 
   const uri = new URL(url);
   uri.searchParams.append('ref', referrerText);
+
+  // Append all existing search params to the redirected URL as well
+  // Note: if existing URL had a ref property then that will override
+  // the referrerText we set above
+  for (const [key, value] of existingSearchParams.entries()) {
+    if (key === 'ref') {
+      uri.searchParams.delete('ref');
+    }
+
+    uri.searchParams.append(key, value);
+  }
+
   return uri.toString();
 };